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Microbial growth and biofilm formation in geologic media is detected with complex conductivity measurements
Author(s) -
Davis Caroline A.,
Atekwana Estella,
Atekwana Eliot,
Slater Lee D.,
Rossbach Silvia,
Mormile Melanie R.
Publication year - 2006
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2006gl027312
Subject(s) - conductivity , biofilm , porous medium , bacterial growth , porosity , environmental scanning electron microscope , scanning electron microscope , hydraulic conductivity , materials science , environmental chemistry , mineralogy , chemistry , chemical engineering , soil science , geology , composite material , bacteria , soil water , paleontology , engineering
Complex conductivity measurements (0.1–1000 Hz) were obtained from biostimulated sand‐packed columns to investigate the effect of microbial growth and biofilm formation on the electrical properties of porous media. Microbial growth was verified by direct microbial counts, pH measurements, and environmental scanning electron microscope imaging. Peaks in imaginary (interfacial) conductivity in the biostimulated columns were coincident with peaks in the microbial cell concentrations extracted from sands. However, the real conductivity component showed no discernible relationship to microbial cell concentration. We suggest that the observed dynamic changes in the imaginary conductivity ( σ ″) arise from the growth and attachment of microbial cells and biofilms to sand surfaces. We conclude that complex conductivity techniques, specifically imaginary conductivity measurements are a proxy indicator for microbial growth and biofilm formation in porous media. Our results have implications for microbial enhanced oil recovery, CO 2 sequestration, bioremediation, and astrobiology studies.